Cables1 links Slit/Robo and Wnt/Frizzled signaling in commissural axon guidance

During neural circuit formation, axons navigate from one intermediate target to the next, until they reach their final target. At intermediate targets, axons switch from being attracted to being repelled by changing the guidance receptors on the growth cone surface. For smooth navigation of the intermediate target and the continuation of their journey, the switch in receptor expression has to be orchestrated in a precisely timed manner. As an alternative to changes in expression, receptor function could be regulated by phosphorylation of receptors or components of signaling pathways. We identified Cables1 as a linker between floor-plate exit of commissural axons, regulated by Slit/Robo signaling, and the rostral turn of post-crossing axons, regulated by Wnt/Frizzled signaling. Cables1 localizes β-catenin, phosphorylated at tyrosine 489 by Abelson kinase, to the distal axon, which in turn is necessary for the correct navigation of post-crossing commissural axons in the developing chicken spinal cord

Cylindrical anisotropic α2\alpha^{2} dynamos

We explore the influence of geometry variations on the structure and the time-dependence of the magnetic field that is induced by kinematic $\alpha^{2}$ dynamos in a finite cylinder. The dynamo action is due to an anisotropic $\alpha$ effect which can be derived from an underlying columnar flow. The investigated geometry variations concern, in particular, the aspect ratio of height to radius of the cylinder, and the thickness of the annular space to which the columnar flow is restricted. Motivated by the quest for laboratory dynamos which exhibit Earth-like features, we start with modifications of the Karlsruhe dynamo facility. Its dynamo action is reasonably described by an $\alpha^{2}$ mechanism with anisotropic $\alpha$ tensor. We find a critical aspect ratio below which the dominant magnetic field structure changes from an equatorial dipole to an axial dipole. Similar results are found for $\alpha^{2}$ dynamos working in an annular space when a radial dependence of $\alpha$ is assumed. Finally, we study the effect of varying aspect ratios of dynamos with an $\alpha$ tensor depending both on radial and axial coordinates. In this case only dominant equatorial dipoles are found and most of the solutions are oscillatory, contrary to all previous cases where the resulting fields are steady.Comment: 15 pages, 8 figure

Dimensionamiento de Almacén a partir de la Planificación de Requerimiento de Materiales en una Fábrica de Revestimiento de Poliuretano

Context: the design of the warehouse is a key factor in the configuration of logistics systems, as it can facilitate the timely management of materials, intermediate and/or final products, improving the time, cost and levels of customer service. To achieve this, experts help is required to integrate within the design an appropriate combination of storage, manipulation of materials and selection of orders. This level of integration, however, has not yet been achieved since the advances in the subject have been addressed from different aspects of the storage problem, but independently.Method: the article presents a method for warehouse layout design in two phases. The first phase defines the variables and parameters that are obtained from the planning of the production; the second phase consists of five stages that culminate in the integral design of the warehouse. In this last phase a modified version of an existing mathematical model of sizing is applied, where a new equation is added.Results: the method is applied to a company that supplies liquid polyurethane in the construction sector. The design generates four options for configuration of shipping and receiving docks and five storage options, where the best option generates an average area, mean real capacity and percentage average of storage utilization of 374,8 m2, 360 pallet and 93,8% respectively. These results are coherent with the dynamics of the company.Conclusions: the method allows evaluating options of the flow configuration and their respective sizing than may influence decisions of great importance in the operational capacity of the company in the short, medium and long term. In the future research is interesting to include new conditions, for example the compatibility of the method with different distributions to the traditional configuration of parallel shelves. Contexto: el diseño del almacén es un factor clave en la configuración de los sistemas logísticos, pues facilita la gestión oportuna de materiales, productos intermedios o finales, mejorando el tiempo, costo y nivel de servicio al cliente. Para lograrlo se requiere el apoyo de expertos que integren en el diseño una combinación apropiada de almacenamiento, manipulación de materiales y selección de pedidos; sin embargo, tal nivel de integración aún no se ha logrado ya que los avances en el tema han sido abordados desde diferentes aspectos del dimensionamiento y de manera independiente.Método: se presenta un método de dimensionamiento de almacenes compuesto de dos fases. En la primera se definen variables y parámetros que son obtenidos a partir del proceso de planeación de la producción; en la segunda, se desarrollan cinco etapas que culminan con el diseño integral del almacén, en la cual se aplica un modelo matemático de dimensionamiento existente que incorpora una nueva ecuación.Resultados: el método de dimensionamiento de almacenes se aplica a una empresa que abastece poliuretano líquido en el sector de la construcción. Se generan cuatro opciones de configuración de muelles de recepción-envío y cinco opciones de almacenamiento; la mejor opción genera un área promedio, capacidad real promedio y porcentaje de utilización promedio de almacenamiento de 374,8 m2, 360 pallet y 93,8% respectivamente, siendo estos resultados acordes con la dinámica de la empresa.Conclusiones: el método es funcional en la organización, puesto que permite evaluar opciones de configuración de flujo y su respectivo dimensionamiento, los cuales pueden influir en decisiones de gran importancia, por ejemplo, en determinar la capacidad operativa de la empresa a corto, mediano y largo plazo. Igualmente, para futuras investigaciones es de interés estudiar nuevas condiciones como es la compatibilidad del método propuesto con distribuciones diferentes a la configuración tradicional de estanterías paralelas.

Modelagem e controle avançado não-linear multivariável por lógica nebulosa : aplicação para um processo de copolimerização

A obtenção de um modelo matemático confiável de um dado processo é um pré-requisito fundamental para o projeto de controladores. Contudo, particularmente para sistemas poliméricos que são intrinsecamente caracterizados por dinâmicas complexas, o delineamento de uma aproximação a partir dos primeiros princípios é uma tarefa bastante árdua e, por vezes, não realizável. Logo, representações matemáticas mais simples, porém reprodutivas das principais peculiaridades do sistema, são bem-vindas. Assim sendo, este trabalho apresenta o desenvolvimento e a implementação de dois esquemas de controle preditivo não-linear multivariável baseado em modelo nebuloso para um processo de copolimerização. Modelos MISO (Multi-Input/Single-Output) lineares e exponenciais são construídos a partir da lógica nebulosa, combinados e aplicados para simulação e predição on-line. Os desempenhos das estruturas de controle propostas foram comparados ao DMC (Dynamic Matrix Control) e a um típico NMPC (Nonlinear Model-based Predictive Control) para o problema servo. Os resultados obtidos comprovaram a eficácia das configurações projetadas

Bis(tetra­methyl­ammonium) tetra­chlorido­zincate(II), phase VI

Phase VI of bis­(tetra­methyl­ammonium) tetra­chloro­zincate(II), (C4H12N)2[ZnCl4], contains three formula units per asymmetric unit. Several short C—H⋯Cl contacts [2.70 (3) and 2.72 (4) Å] are observed, but they are believed to participate only in van der Waals inter­actions. The crystal studied exhibited inversion twinning

Stochastic model to assess bioeconomic impact of PRRS on pig farms in Costa Rica

Despite the economic importance of PRRS and its high prevalence in Costa Rica, there are no studies on the bioeconomic impact of the disease in the country or, even, in Central America. Such studies are essential in finding cost-effective preventive measures tailored for different production circumstances. Therefore, the objective of this study was to evaluate economic and production parameters of a PRRSV-infection for a medium-sized farrow-to-finish pig farm system in Costa Rica with a farm-level stochastic Monte Carlo simulation model. The effect of PRRS was assessed by scenario analysis, in which a baseline PRRS-free situation was compared against three alternative scenarios that assumed low, medium and high PRRS effects. The PRRS effects were based on data from local farms, scientific literature and expert opinion. Sensitivity analyses were performed to assess the impact of key input parameters on output variables. Results show that at the animal level, changes between the baseline and the PRRS-high scenario were estimated as: + 25 d in age to slaughter, - 9.9 pigs to slaughter (per breeding sow/yr), + 6% annual replacement rate, - 255 d in sow productive lifetime, - 6.9 mo in age at culling of sows, and + 24 non- productive days. For a medium size local farm (n = 588 sows), a reduction of 5826 fat pigs to slaughter per farm/yr from baseline compared to PRRS-high scenario was observed. PRRS-induced loss per farm per year was estimated at -US $142,542, US$180,109 and -US $524,719 for PRRS-low, medium and high scenarios, respectively. Revenues/costs ratio changed from 1.12 in the baseline to 0.89 in the PRRS-high scenario. The production cost per kg carcass weight increased from US$2.63 for the baseline to US $3.35 in the PRRS-high scenario. PRRS-induced loss was estimated at US$77.1 per slaughtered pig/yr and US $892 per breeding sow/yr for the PRRS-high scenario. Results from the model indicate that pig farms with medium to high prevalence of PRRS will require optimal market conditions in order to have positive economic outcomes. These results can be helpful in the design of better control strategies for PRRS

Variability of the prevalence of depression in function of sociodemographic and environmental factors: ecological model

Major depression etiopathogenesis is related to a wide variety of genetics, demographic and psychosocial factors, as well as to environmental factors. The objective of this study is to analyze sociodemographic and environmental variables that are related to the prevalence of depression through correlation analysis and to develop a regression model that explains the behavior of this disease from an ecological perspective. This is an ecological, retrospective, cross-sectional study. The target population was 1,148,430 individuals over the age of 16 who were registered in Aragon (Spain) during 2010, with electronic medical records in the community’s primary health care centers. The spatial unit was the Basic Health Area (BHA). The dependent variable was the diagnosis of Depression and the ecological independent variables were: Demographic variables (gender and age), population distribution, typology of the entity, population structure by sex and age, by nationality, by education, by work, by salary, by marital status, structure of the household by number of members, and state of the buildings. The results show moderate and positive correlations with higher rates of depression in areas having a higher femininity index, higher population density, areas with a higher unemployment rate and higher average salary. The results of the linear regression show that aging +75 and rural entities act as protective factors for depression, while urban areas and deficient buildings act as risk factors. In conclusion, the ecological methodology may be a useful tool which, together with the statistical epidemiological analysis, can help in the political decision making process

Nematodos asociados con el cultivo del plátano (Musa AAB o ABB) en el Valle del Cauca.

Se realizó un reconocimiento cualitativo y cuantitativo de los principales nemátodos fitoparásitos asociados con el cultivo de plátano. El estudio se llevó a cabo en fincas de agricultores minifundistas localizadas en los municipios vallecaucanos de El Bolo, Rozo y Cerrito. Se analizaron 87 muestras tanto de suelo como de raíces, discriminados así: 31 en El Bolo, 25 en Rozo y 31 en Cerrito, para un área total de 88.7 ha, aproximadamente. Se encontró que los géneros más importantes por su incidencia, población y distribución observada fueron: Meloidogyne, Helicotylenchus, Pratylenchus, Rotylenchulus y Radopholus. El género Meloidogyne se encontró ampliamente distribuído en las 3 zonas. Otros nemátodos que se encontraron asociados con este cultivo fueron: Trophurus sp, Paratylenchus sp. Hoplotylus sp. Criconemoides sp. Trichodorus sp. Ditylenchus sp. Tylenchorhynchus sp. Psilenchus sp. y Xiphinema sp. Las plantaciones donde se registraron altas poblaciones de nemátodos en general, presentaron síntomas de amarillamiento y clorosis del área foliar, racimos pequeños y raquíticos, tallos delgados en su parte inferior, necrosis y muerte de raíces, ausencia de raicillas y embalconamiento de la plantaPlátano-Musa sapientu